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JOHN BREWER, OF PHILADELPHIA, PENNSYLVANIA.

Letters Patent No. 79,198, dated June 23, 1868.

IMPROVEMENT IN BXPANDING-MANDREL.

@In Stimuli marit in in tigen @dans itent mit nmtiug part nf its samt.

TO ALL WHOM IT MAY CONCERN:

-Be it known that '1, JOHN BREWER, of the city of Philadelphia., and State of Pennsylvania, have invented a new and improved Adjustable Contraction- Tapg and I do hereby declare that the following isa full, clear, andexact description of. the same, reference being had to the accompanying drawing, and to the letters of reference marked thereon. i v

. My invention consists o f one ormore cutters, arranged around a hollow circular stock, and having such relation to the stock and a cutter-head-or holder, that they are contracted or'expanded by the raising or lowering ofth'e cutter-head. fhe tap is especially adapted to the manufacture of' gas and steam-fittings, and other connections for wrought-iron `pipes. i

On reference to the accompanying drawing, forminga part of this specification- Figure 1 is a viewzof thetap, with a section of the tting, showing the cutters and thread.

Figure 2 is a vertical section, with the cutters contracted, to admit of the tap being withdrawn from the fitting without reversing the tap or stopping the machine, and i Figure 3 is an end view of the cutter-head or holder. y

Similar letters refer to similar parts in the several views.

Ais a hollow cylindrical stock, having one or more spirally-inclinedslots, a, about midway of its ends, and oneor more-radial openings, Z, near its lower end,.which extend in the direction of its length. B is a swivelroch-fitting snugly the stock A; its lower end is,'for a short distancerslightly'reduced,in diameter, to receive the cap C, which is pinned lor otherwise secured to it. D is a screw-rod, its upper end heing p'rovidedwith a head,f, which takes into the. cap C, and is thereoy'prevented `from lifting or rising, while at the'same time it is allowed a perfectly free rotation. E is a cylindrical plug, cutterholder, or head, which takes on the screwrod D. Ajam-mft,.c, preserves it in its relative .position after it has been adjusted. Made longitudinally on the cutter-head E, and at equal distances apart, are several, inclined grooves, d, any number of which can be used. They receive the inner ends ofthe adjustable contraction-cutters F F F, the grooves in the-cutters taking over the lipsg of the grooves in the cutter-head, and the ends of the cutters resting firmly on thebottoms ofthe same, the cutters ttingsnugly the radial openings b in the stock A.

The distance of the top ofthe cutter-holder E fromthecap Cadjusts the gauge of the cutters, which distance is regulated by screwing the" cutter-holder up or down on the screw-ro'dD, after which the swivel-rod B and its lacconipanying parts are inserted into the stoek'A until the upper ends 'of the inclined grooves in the cutter holder arein a line with the lbottom. end s of the radial'openings b, in the stock. The cutters F are`then s'et in the lopenings 6; the swivel-rodsmovedup the stockruntil either hole e in it adjusts itself to the slots a, care ybeing taken to press firmly-on the cutters while pushing the swivel up into `the stock. A pin or lever, G, is n'owipassedthrough tho slots in the stock and the "hole in the pin, projecting both ways-from the stock, being llocked by taking into the corners orlower ve'ndsof tho slots a.' The taf has now the required gauge for tapping' fittings, as is shown in fig. 1, where it has gone. the required distance into the fitting H. The pin or lever G is now held fast, and the stock A continuing tol rotate, it is carried up the slots a,the swivel-rodB and lts accompanying parts being carried up withit, ilntil it takes into or is locked in the upper ends of the saine slots. The Acutters F having only aradial movement, and beingheldin the inclined grooves of the cutter-head, it follows, since the groovesy incline outwardly or towards the ontei'end of the cutter-head, that the cutters must be conf tractd when the cutter-head rises in the stock, as is shown in iig. 3, so as to be easily Withdrawn froin the tting H, without stopping the drill-press or tapping-machine, or reversing the tap; and for the same reason, when the 'cutter-head descends,.the cutters ride or `travel up the inclined grooves, and are expanded.

The cutter-head can be adjusted by niany other'known mechanical devices than by the screwrotl D; there, fore I do not confine myself to its use; neither do I conne myself to any method of holding the cutters in the inclined grooves of the cutter-head. I v Iat first proposed to raise and lower the cutter-head by meausof a pin, which projected throughhorizontal slots in opposite parts of thesurface of the stock, linto inclined slots formed i'n 'a collar on the stock, the collar' being held from raising or lowering by set-screws, which took into a. groove formed around the stock, but was at liberty to, rotate freely. Handles for turning the collar were fixed oppositely to it.`

What I claim as my invention, and desire to secure by Letters Patent, `sy The cfcter-hon Ef in combination with the screw-rod D,"c ap Q', swive1.B,` slotted stock A, and the rod Gr,y as shown. v i

In testimony whereof, I hereunto sign my name to this specification in presence of two snbseribing witnesses.

JOHN BREWER.

Witnesses:

FRANCIS D. PAsToRIUs, W. W. DoUenERTY. 

